Extract ExtensionFunctionRegistry from ExtensionFunctionDispatcher.

build/json_schema_compile.gypi

Index: build/json_schema_compile.gypi
diff --git a/build/json_schema_compile.gypi b/build/json_schema_compile.gypi
index b44fe917a6302a5ea8d1b713bbb56bac32e92e66..6c8f69c5daf48a068d8159bed8613627bf11b665 100644
--- a/build/json_schema_compile.gypi
+++ b/build/json_schema_compile.gypi
@@ -5,7 +5,8 @@
 {
   'variables': {
     # When including this gypi, the following variables must be set:
-    #   json_schema_files: an array of json files that comprise the api model.
+    #   json_schema_files: a list of json files that comprise the api model.
+    #   idl_schema_files: a list of IDL files that comprise the api model.
     #   cc_dir: path to generated files
     #   root_namespace: the C++ namespace that all generated files go under
     # Functions and namespaces can be excluded by setting "nocompile" to true.
@@ -53,6 +54,7 @@
     },
     {
       'rule_name': 'genapi_idl',
+      'msvs_external_rule': 1,
       'extension': 'idl',
       'inputs': [
         '<(api_gen_dir)/any.cc',
@@ -72,7 +74,7 @@
         # TODO(calamity): uncomment this when gyp on windows behaves like other
         # platforms. List expansions of filepaths in inputs expand to different
         # things.
-        # '<@(json_schema_files)',
+        # '<@(idl_schema_files)',
       ],
       'outputs': [
         '<(SHARED_INTERMEDIATE_DIR)/<(cc_dir)/<(RULE_INPUT_ROOT).cc',